Turdinirmus calleipus Gustafsson & Li & Tian & Ren & Sun & Zou 2025, sp. nov.

Turdinirmus calleipus sp. nov. urn:lsid:zoobank.org:act: 45166825-E353-4455-9050-16CCC59C6DEF Figs 14–20; Table 1 Differential diagnosis Turdinirmus calleipus sp. nov. can be separated from all known species of Turdinirmus by the narrow and pointed frons, contrasting with the broader, often near flat, frons of congeners. Etymology The specific epithet is derived from ‘kalleípō’, ancient Greek for ‘abandoned’, referring to the unknown type host of this species. Material examined Holotype (ex “woodpecker” [likely an error]) CHINA • ♂; Jiangxi Province, Geyang; date unknown; Xiongbiao Wang leg.; box E0026020, slide 5; NHMC. Paratypes (ex “woodpecker” [likely an error]) CHINA • 3 ♀♀; Jiangxi Province, Geyang; date unknown; Xiongbiao Wang; box E0026020, slides 5, 7; NHMC. Type host “Woodpecker” [likely an error]. Type locality Geyang, Jiangxi Province, China. Description Both sexes Head trapezoidal, preantennal area strongly narrowed anteriorly, lateral margins of preantennal head straight, frons concave (Fig. 16). Marginal carina narrowing conspicuously towards frons. Dorsal anterior plate longer than wide. Head structures and chaetotaxy as in Fig. 16. Thoracic and abdominal segments and chaetotaxy as in Figs 14–15. Sternal plates in both sexes poorly sclerotised and illustrated approximately. Male Abdominal chaetotaxy: ss present on segments II–VIII; tps and aps absent; psps present on segments IV–VII; ps present on segments IV–VIII; sternite II with 1 sts on each side, sternites III, IV (one side only, one sts on other side) and VI with 2 sts on each side, on sternite V only 1 sts on each side in single examined male, but this may be specific to this specimen. Basal apodeme widening distally (Fig. 17). Mesosome slightly distorted in holotype, and illustrated as accurately as possible. Proximal mesosome short, slightly concave (Fig. 18); mesosomal lobes somewhat angular laterally; distal mesosome with fringed lobes. Gonopore wide, with lateral ends splayed anteriorly; 3 gpmes on each side of gonopore and 1 lpmes on each side on lateral margin of mesosome. Parameres as in Fig. 19; parameres in holotype folded under mesosome, and here rotated in the illustration for clarity. Measurements as in Table 1. Female Abdominal chaetotaxy: ss present on segments II–VIII; tps and aps absent; psps present on segments IV–VII; ps present on segments IV–VIII; sternites II–III with 2–3 sts on each side, and sternites IV–VI with 2 sts on each side. Female subgenital plate trapezoidal (Fig. 20); vulval margin with 6–9 short, slender vms, 10–12 short, thorn-like vss, 3–5 short, slender vos on each side; distal 1 vos median to vss. Measurements as in Table 1. Remarks The natural host of this species is unknown, but likely some species of thrush. The slide labels on both the holotype and the paratype slides are marked only with the name “woodpecker” in Chinese. There are at least 11 species of woodpeckers in Jiangxi Province (Liu & Chen 2024), but no further clue to the identity of the host is given on the slide. The slide of the holotype is marked to denote that the host may be wrong, presumably in Sikong Liu’s handwriting. However, lice in the genus Turdinirmus are otherwise not known from woodpeckers, but from thrushes (Passeriformes: Turdidae), mainly hosts in the genus Zoothera Vigors, 1832, but also on Geokichla Latham, 1790, and Turdus Linnaeus, 1758. Two nymphs and one female of an unidentified species of Penenirmus Clay & Meinertzhagen, 1938b, mounted on a separate slide, are ostensibly from the same host specimen; this genus also occurs on songbirds, and is replaced in woodpeckers by the genus Picophilopterus Ansari, 1947, further indicating that the natural host of T. calleipus is not a woodpecker. Most likely, the host information on the slides of T. calleipus is incorrect, and the natural host of this species is a thrush. At least 12 species of thrush occur in Jiangxi Province (Liu & Chen 2024), and further collections are necessary to establish the natural host of T. calleipus. Few species of lice have been described without a type host, but in principle, host associations are not an innate characteristic of the lice themselves, and thus not necessary for the description of species, given that morphological characters are sufficient to separate the species from all congenerics. In this case, the head shape separates T. calleipus from all known species of Turdinirmus, and we therefore describe this species as new. As such, T. calleipus is illustrative of the principle that the type host and the natural host of a louse are separate concepts, and only the latter one is biologically relevant (Palma 2015; Gustafsson 2023).